90 deg curve with transitions equal on each leg

richard_t

Member
Location
nr Spalding
Hi

(I'm pretty sure, in the dim distant past I've asked this before...)

How I can I have a 90 degree curve, with equal transitions at each end? Obv. with 2 templates, but it's the equal bit I'm struggling with.

Thanks in advance.

Richard
 
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Martin Wynne

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Location
West of the Severn UK
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@richard_t

Hi Richard,

Yes, I recall a previous question about this, but I can't find it at present. :confused:

But it's fairly easy:

1. easement transition from straight to curve. The length of straight can be zero.

2. with the peg on the straight end, CTRL-0, geometry > swing angles (in degrees)... .

3. set the swing angle to half the total turn, in this case 45 degrees.

4. put the peg at the curved end, CTRL-1.

5. tools > make mirror on peg.

If setting the swing angle fails, try swapping end-for-end (facing-trailing) before you start. The peg must be at CTRL-0.

It also works for a C or S transition without any straight, providing the peg is at CTRL-0 to start, which can be inside the transition zone.

cheers,

Martin
 
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richard_t

Member
Location
nr Spalding
Hi

Thanks for that - easy when you know how.

As a follow up question: If I want the start of one transition to start at X: 0, Y: 2000 and the start of the other transition to start at X: 2000, Y: 0 - with a minimum radius of 1450mm, how can I work out how long the transition zone should be? Or is it trial and error?

Thanks again.

Richard
 
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Martin Wynne

Admin
Location
West of the Severn UK
Info
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Enjoy using Templot?
Thanks.

Please do not send requests for help direct to me via email.

Post your questions on the forum where everyone can see them and add
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@richard_t

Hi Richard,

Not trial and error, but it does need a human eyeball. :)

1. put a line in the background shapes at 45 degrees:

trans45_0.png



2. set up your template from straight down to 1450mm radius transition.

3. adjust the transition zone length (] key) until the radial centre is exactly on the line:

trans45_1.png


Zoom in closely on it to make a precise adjustment.

4. then continue as before to set the length to 45 degrees and mirror:

trans45_2.png


5. delete the background shape line.

If you need some other turn than 90 degrees, start from a vertical line in the background shapes, through the intersection of the straight tracks, and use the rotate by... function to set the line at half the angle.

p.s. this is a perfect example of why Templot uses the mouse actions, instead of grab handles like most other Windows drawing programs. You can zoom in as close as you like on that radial centre, and still use any mouse action you like to adjust it. You don't need to see a handle on the screen to grab.

cheers,

Martin.
 
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